Aviation contrails, short for “condensation trails,” are the linear clouds often seen forming behind aircraft as they fly through the atmosphere. These trails consist of ice crystals and form when the hot, humid exhaust from aircraft engines mixes with the colder air at high altitudes. Contrails can persist and spread out, forming cirriform clouds that can cover large areas of the sky.
These cirriform clouds have a complex impact on Earth’s climate. On one hand, they can reflect sunlight back into space, which has a cooling effect on the planet. However, they can also trap heat radiated from Earth’s surface, known as infrared radiation, which contributes to warming the atmosphere.
The overall effect of contrails and cirriform clouds on climate heating is still an area of active research, as it depends on various factors such as the altitude of the contrails, the type of aircraft, and the atmospheric conditions. However, there have been many studies that have shown a dramatic increase in local temperatures from cirriforms. In fact, those studies claim that there could be more warming from these clouds than greenhouse gasses.
Studies suggest that contrails and cirriform clouds from aviation may have a small but non-negligible effect on global climate heating, particularly in regions with high air traffic, not just local. Efforts to mitigate this impact include optimizing flight paths to avoid areas where contrails are more likely to form and developing new aircraft engine technologies to reduce emissions.